A system for backing up data in a volatile memory for a disk array system has been known as a memory data backup system. For example a backup system described in Japanese Patent Application Laid-Open (Kokai) Publication No. 2009-237881 discloses that it supplies power from a battery to a memory controller and a main memory and saves data from the main memory to a nonvolatile memory at the time of a power failure.
It is also known that as a conventional example of a data backup system for a volatile memory, an interface dedicated for backups is provided in a memory controller and data in a cache memory is transferred via the dedicated interface to a nonvolatile memory such as SSD at the time of a power failure.
A conversion circuit for mutually converting a protocol for the dedicated interface to/from a protocol for an interface of a nonvolatile memory is provided between the dedicated interface and the nonvolatile memory.